J2EE常用工具类—Hibernate操作

package cn.org.jshuwei.j2ee.util;

import java.io.Serializable;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

/**
* 
* Hibernate操作的工具类
* 
* @author huwei(jshuwei.org.cn)
* @since 1.0
* 
*/
public class HbnUtil {
    private static SessionFactory sf;

    /**
     * 得到SessionFactory
     * 
     * @since 1.0
     * @return 返回SessionFactory
     */
    public static SessionFactory getSessionFactory() {
        if (sf == null || sf.isClosed()) {
            try {
                sf = new Configuration().configure().buildSessionFactory();
            } catch (HibernateException e) {
                e.printStackTrace();
            }
        }
        return sf;
    }

    /**
     * 得到Session
     * 
     * @since 1.0
     * @return 返回Session
     */
    public static Session getSession() {
        getSessionFactory();
        return sf.openSession();
    }

    /**
     * 释放SessionFactory
     * 
     * @since 1.0
     */
    public static void releaseSessionFactory() {
        if (sf != null && !sf.isClosed()) {
            sf.close();
        }
    }

    /**
     * 保存对象
     * 
     * @since 1.0
     * @param obj
     *            需要保存的对象
     */
    public static Serializable add(Object obj) {
        Session session = null;
        Serializable ret = null;
        try {
            session = getSession();
            session.beginTransaction();
            ret = session.save(obj);
            session.getTransaction().commit();
        } catch (HibernateException e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        } finally {
            if (session != null) {
                session.close();
            }
            releaseSessionFactory();
        }
        return ret;
    }

    /**
     * 删除对象
     * 
     * @since 1.0
     * @param obj
     *            需要删除的对象
     */
    public static void delete(Object obj) {
        Session session = null;
        try {
            session = getSession();
            session.beginTransaction();
            session.delete(obj);
            session.getTransaction().commit();
        } catch (HibernateException e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        } finally {
            if (session != null) {
                session.close();
            }
            releaseSessionFactory();
        }
    }

    /**
     * 更新对象
     * 
     * @since 1.0
     * @param obj
     *            需要更新的对象
     */
    public static void update(Object obj) {
        Session session = null;
        try {
            session = getSession();
            session.beginTransaction();
            session.update(obj);
            session.getTransaction().commit();
        } catch (HibernateException e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        } finally {
            if (session != null) {
                session.close();
            }
            releaseSessionFactory();
        }
    }

    /**
     * 查找对象
     * 
     * @since 1.0
     * @param clazz 需要查找的对象类型
     * @param id
     *            需要查找的对象的id
     */
    public static Object find(Class clazz,Serializable id) {
        Session session = null;
        Object obj=null;
        try {
            session = getSession();
            obj=session.get(clazz, id);
        } catch (HibernateException e) {
            e.printStackTrace();
        } finally {
            if (session != null) {
                session.close();
            }
            releaseSessionFactory();
        }
        return obj;
    }
}